INVESTIGATION OF A SHORT-PERIOD (001)HGTE-HG0.6CD0.4TE SUPERLATTICE BY TRANSMISSION ELECTRON-MICROSCOPY

A molecular beam epitaxially grown short-period (001) HgTe-Hg0.6Cd0.4Te superlattice was studied by means of transmission electron microscopy and high-resolution electron microscopy (HREM). Cross sections of the as-grown samples revealed good epitaxial features and surprisingly strong contrast between HgTe and Hg0.6Cd0.4Te layers in spite of the small difference in Cd concentration between the wells and the barriers. The fact that the variation in Cd concentration is so small is due in part to interdiffusion between the very narrow wells and barriers, which are only four and six monolayers wide, respectively. Precipitates of dimensions 1 by 12 nm have been identified in HREM images as the monoclinic, high-pressure phase of elemental Te.